Microwaves: myths and reality

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Microwaves: myths and reality




by Christophe » 14/11/06, 07:13

This topic follows on from the following topic on the nature, effects and use of microwaves.

laboratory-econological / estimate-of-return-to-the-oven-microwave-t2365.html
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by Christophe » 14/11/06, 07:22

delnoram wrote:that's a good answer?


No these are observations ... not explanations on the pkoi of the nature of light ...

Besides, everything is summarized in a few sentences:

1) "But how to reconcile the continuous (waves) with the discontinuous (particles)?
This is the whole paradox of the wave-particle duality "

2) This precise point can pose a very disturbing philosophical problem: Is objective reality (if it exists independently of the human mind) accessible? Or are we condemned to observe only a world of deceptive appearances?


Otherwise the paragraph "where the light comes from" refreshed my memory (course lazer) ... but once again: if photo is electron are "of the same nature" (or almost) ... I don't 'tjrs not always (and this is the case since I heard about the operation of a lazer for the first time) to explain to me the creation of a photon (especially if it is corpuscular) when an electron change diaper ...

Have an idea: you should ask the question about Futura Science! But apart from spitting out the physics books, I doubt that we have a CLEAR AND CONSTRUCTIVE answer ... kk1 wants to try it?
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by Christophe » 14/11/06, 07:28

Woodcutter wrote:
Angel wrote:Microonde - Personally I do not use anymore:
It's not good for health: : Evil:
http://www.onnouscachetout.com/themes/a ... lantes.php
Wouaaaahhh : Lol:

Super, the scientific article ... : Mrgreen:


Funny to day nine, the MOs even disintegrated the rest of the sheet that was left!

ps: am downright not for MO because ultimately we have very little perspective and who can claim to know what exactly is water? But there is abuse ...
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by Christophe » 14/11/06, 07:36

bobléponge wrote:First of all, there are two small developments: the MOs excite the dipolar molecules, but only the water has a low viscosity enough to allow its molecules to stir properly and produce heat. The oil theoretically has too high a viscosity (and molecules too big) to be able to warm up. The results of your experiments seem odd to me, I think I will test on my side.


We were also surprised but you will check for yourself ... I don't think you find such different results ... Experience takes precedence over theory (difficult for teachers to swallow ...)

bobléponge wrote:Where can I find this data? In addition, the waves come from the top of the oven, but can we assimilate them to plane waves?


Uh, I'm overwhelmed (sorry I quit school 5 years ago ... and it goes quickly you'll see : Cry: ) ... Requests on Futura Sciences : Cheesy:

bobléponge wrote:And if all its considerations you spend above, you can always give me ideas of funny experiments (or not) involving heating MO to impress the jury!


There was a funny link with lots of exp on this subject: https://www.econologie.com/forums/estimation ... t2365.html
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by iota » 14/11/06, 08:26

"Where could I find this data? Also, the waves come in through the top of the oven, but can they be likened to plane waves?"


The magnetron is often on the side of the oven behind or behind the timer, but never on top.
There is very often a waveguide that guides the mo to the top of the oven.
Often there is also a paddle stirrer in the path of the mo which causes them to go anywhere in the oven so that there is not just one zone that "cooks".
So the plane waves ... :|
they are flat at the exit of the magnetron maybe, but in the oven they go in all directions.

In addition, I thought of something:
After some hacks with the vacuum tubes (the magnetron is a vacuum tube, one of the last with the cathode ray tube).
I found that the tube still worked even when the current was cut thanks to the capacitor which still supplied current and when the filament was still hot.
In a microwave there are filaments and condos that have exactly the same purpose.
I told myself that when you open the oven door, the magnetron is supposed to be stopped.
But what stopped? the 240v in the sector? in this case the magnetron still works for at least a second ... : Shock:
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by iota » 14/11/06, 08:59

Other explanations (I took this subject along the way, I had not read the previous locked):
I'll tell you EVERYTHING I know about microwaves and ovens!
: Mrgreen:

The magnetron generates at a frequency of 2450Mhz or 2.45 Ghz if you want.
We can "see" this frequency emission with a video transmitter which operates on this same frequency (for more info ask me ...).
It allows you to see leaks from the croonde, but I point out that at 2-3 meters it still parasites the transmitter.

Concerning the loss between the consumption and the heating of the liquid:
There are losses in the power section (like the one already said I don't know who) because of the transformer which comes out of 1500volts for the magnetron and 1.5volts under pa smal of amperes (not negligible that!) For the filament.
The losses in a transformer are not negligible.
The 1500volts losses when passing through the condo and the diodes (voltage booster and smoothing).
Losses in the magnetron (that we understood).
Losses at the exit of the magnetron in the waveguide and then through a mica plate.

There are not 36 manufacturers of magnetron !!!!
panasonic
samsung
emerson (not sure)
kenwood
daewoo (not sure)

if it is found you all have the same magnetron!

The best way to compare is to dismantle the oven, because not one is made exactly the same (waveguide or not, wave agitator or not ... etc)

Regarding the combi, it is normal that the resistance does not spark since it is connected to the mass of the oven and does not have spikes.
These are the spikes that cause mini-sparks (hence the name spike effect).
The grid that can be placed in the oven has in principle no spikes and is circular (no antenna effect of a metal loop)

I think I said it all : Mrgreen:
if that can enlighten you :!:
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by iota » 14/11/06, 09:04

I forgot:

A tube is not effective as soon as it is energized.
for most tubes you have to wait ten seconds for it to work "normally".
It reaches its optimum functioning after a few minutes (variable according to the brands, models and type of tube).
For comparison, we can trust a cathode ray tube whose image only appears after a few seconds.
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by Christophe » 14/11/06, 09:10

During the tests we found that the power absorbed by the ovens decreased with the operating time.

It was not possible for us to calculate "cold" or "hot" performance simply to make this observation ...
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by iota » 14/11/06, 09:43

A cold filament consumes more than hot.
This is certainly applicable to magnetron and probably to the other components which have a delay before arriving at a cruising speed.
The filament of the bulb undergoes the same rules, when starting 10 watts (hypothesis) and after qqs seconds it drops. (5w I believe the oven bulbs)

Magnetron on heating also has an effect on the high voltage present at the anode.
When starting there is a peak, then it goes down for a few seconds until it stabilizes. (peak from 50 to 100 volts in practice)
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by delnoram » 11/02/07, 11:54

microwave leak test.
A hyper basic detector allowed me to make the following observations:
No leaks all around the oven ... except in front of the oven glass.
Leak that the detector perceives only within 10 cm of said window.
It is much more important when the oven is empty than when there is a simple glass of water.
In my opinion, the more the oven contains material capable of absorbing microwaves, and there are less leaks.
A word of advice, however, avoid contemplating too long and too often what is cooking : Cheesy:
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